Former president George HW Bush has been taken to hospital in Houston with an infection, just after attending the funeral of his wife Barbara, a spokesman said.
Jim McGrath said on Twitter that the 93-year-old Bush is "responding to treatments and appears to be recovering". He was admitted on Sunday morning to Houston Methodist Hospital after an infection spread to his blood, Mr McGrath said.
Barbara Bush was laid to rest Saturday in a ceremony attended by her husband and former presidents Bill Clinton, Barack Obama, George W Bush and their wives, along with current first lady Melania Trump.
The elder Bush uses a wheelchair and an electric scooter for mobility after developing a form of Parkinson's disease, and he has needed hospital treatment several times in recent years for respiratory problems.
A year ago this month, Mr Bush spent two weeks in the hospital for treatment of pneumonia and chronic bronchitis, a constant irritation of the lining of tubes that carry air to one's lungs.
Mr Bush's doctors said chronic bronchitis is a condition more prevalent with age and can aggravate the symptoms of pneumonia.
Bush was in hospital for 16 days in January 2017 for pneumonia. During that hospital stay, which included time in intensive care, doctors inserted a breathing tube and connected him to a ventilator.
He also was taken to hospital in 2015 in Maine after falling at home and breaking a bone in his neck, and in December 2014 for about a week for shortness of breath. He spent Christmas 2012 in intensive care for a bronchitis-related cough and other issues.
George Herbert Walker Bush served as president from 1989 to 1993. Born June 12 1924, in Milton, Massachusetts, Mr Bush also served as a congressman, CIA director and Ronald Reagan's vice president.